Manufacture of wrought iron



May 13, 1941. F, w wHlTE 2,241,434

I I MANUFACTURE OF WROUGHT IRON Fi1 ed July 19, 1939 4 Sheets-Sheet 1 INVENTOR 4 Sheets-Sheet 2 May 13, 1941. F. w. WHITE MANUFACTURE OF WROUGHT IRON Filed July 19, 1939 May 13, 1941.

F. w. WHITE MANUFACTURE OF WROUGHT IRON 4 Sheets-Sheet 5 Filed July 19, 1939 LANA ' y 13, 1941 F. w. WHITE 2,241,434

' MANUFACTURE OF WROUGHT IRON I Filed July 19, 1939 4 Sheets-Sheet 4 INVENTOR We oe rick l ll W/W'fe Patented May 13, 1941 UNITED STATES PATENT. oFF ca MANUFACTURE OF. WROUGHT IRON Frederick W. White, New Brighton, P a., assignor to A. M. Byers Company, Pittsburgh, Pa., a corporation of Pennsylvania Application July 19; 1939, Serial No. 285,318

12 Claims.

This invention relates to the manufacture of wrought iron by the Aston process and more particularly to an improved method and improved apparatus whereby a superior wrought iron product is produced and molten ferrous material at relatively low temperature may be employed.

The aston process for the manufacture of wrought iron is now well known and in a preferred method of procedure comprises pouring molten ferrous material into a bath of molten slag so'ithat the solidified or partly solidified granules of ferrous material formed during the pouring are individually coated with slag and welded together to form at the bottom of the slag receptacle a compressible mass or ball of wrought iron. The ball thus formed can be compressed to form a bloom which may then be rolled or reduced to a billet or any other desired form.

For yearsthe standard practice in the manufacture of wrought iron by the Aston process has been to melt the ferrous material in cupolas and then refine it by bessemerizing. The bessemerized ferrous material has then been transferred to the so-called shotting machines where it has been poured out of lip pouring laddles into baths of molten slag.

A disadvantage in the use of lip pouring ladles in the shotting machines is the sculling of the molten ferrous material therein. The metal tends to solidify around the pouring lip of the ladle, this tendency being accentuated due to the fact that the surface metal is at the lowest temperature and hence closest to the solidification point. The sculling is manifested by accretions of solidified metal at and adjacent the pouring lip, which accretions undesirably influence the cross-section of the pouring stream, tending to spread out the stream and make it thin and irregular. This in turn results in inadequate penetration of the ferrous material into the slag.

It has been found in practice that sculling tends to occur with the use of lip pouring ladles at any practicable temperature of the metal, but the lower the temperature of the metal the more pronounced has been the sculling. In order to reduce sculling the temperature of the metal as delivered to the shotting machine ladles has been raised in the converter to about 3200 R, which is higher than would otherwise be necessary and undesirably high from the standpoint of cost. However, even with metal at about 3200 F. some sculling may still occur.

The use of an open hearth furnace in the preparation of the molten ferrous material has certain advantages. Open hearth metal is normally tapped at a temperature in the neighborhood of 2950 F. While it is possible to operate an open hearth furnace at temperatures up to 3000 F. and over, if the temperature substantially exceeds this value the strains on the furnace parts are magnified and the life of the furnace shortened. It has been found in practice that it is not practicable to operate open hearth furnaces at a regular operating temperature substantially higher than 3000 F. I have melted and refined in an open hearth furnace at temperatures ranging from 2900 F. to 3000" F. ferrous material for use in the" manufacture of wrought iron by the Aston process, but the sculling resulting when such ferrous material is attempeted to be poured out of the lip pouring ladies of the shotting machines has been so pronounced that satisfactory results were diificult or impossible of attainment. The sculling interferes with the uniformity of the stream, causing it to spread out and strike the surface of the slag somewhat in fan shape so that the penetration is uite inadequate.

Bottom pour ladles of the standard type employing stoppers have been tried out in the manufacture of wrought iron by the Aston process, but such ladles are unsatisfactory. Trouble is constantly encountered with the stopper and its associated mechanism and also the head of metal above the nozzle is not constant but gradually decreases from a maximum at the beginning of the pour to zero at the end of the pour. For these reasons the use of bottom pour laddles was given up years ago and when the Ambridge plant of A. M. Byers Company was erected in 1929 such plant was equipped exclusively with shotting machines having lip pouring ladies in which the head of liquid above the pouring lip can be maintained substantially constant throughout at least the greater portion of the pour. These shotting machines have been used continuously since 1929 with the disadvantages above pointed out. Their impracticability for use with ferrous material melted and refined in an open hearth furnace has been demonstrated, as mentioned above.

The desirability of employing molten ferrous material at temperatures in the neighborhood of 2900 F. to 3000 F. has long been appreciated, but the use of metal at such low temperatures has not heretofore been practicable because of pouring difliculties, as explained above. As indicated above, it has been desirable to employ ferrous material prepared in an open hearth furnace, but this has not heretofore been feasible because of the difficulties encountered incident to sculling in pouring open hearth metal.

I have discovered that ferrous material melted in an open hearth furnace or otherwise prepared and at temperatures as low as about 2900 F. to 3000 F. can be poured into a slag bath in the manufacture of wrought iron by the Aston process without dimculty and indeed to great advantage by the use of a tilting ladle equipped with a nozzle through which the molten ferrous material is poured, the nozzle controlling the cross-section of the pouring stream and maintaining such stream relatively compact and dense so that greater penetration of the molten ferrous material into the slag is obtained. The tilting movement of the ladle is preferably controlled sothat during at. least the greater portion of the pour the head of molten ferrous material above the nozzle is substantially constant. This insures uniformity of the stream during at least the greater portion of the pour. Moreover, despite the relatively low temperature of the metal no appreciable'sculling at or immediately adjacent the nozzle is encountered. When the ladle is filled the nozzle or orifice is above the level of the molten ferrous material and to pour the molten ferrous material the ladle is preferably tilted to bring the nozzle a predetermined distance below the level of the molten ferrous material in the ladle and then progressively tilted to maintain the head of molten ferrous material above the nozzle substantially constant. Consequently throughout the greater portion of the pour the molten ferrous material at the nozzle is relatively hotas compared with that at the surface, the nozzle being submerged. In actual practice no appreciable sculling occurs, as mentioned above. Occasionally a thin film of solidified metal may form over the nozzle at the very end of the pour, but this is easily broken away by introducing a rod through the nozzle.

Wrought iron made by my improved method and with my improved apparatus is of superior quality due to the controlled dense stream of molten ferrous material poured into the slag bath, resulting in desirable and uniform penetration of the ferrous material into the slag. The use of ferrous material prepared in an open hearth furnace is feasible and hence the demand for wrought iron for the fabrication of various products in which open hearth metal rather than Bessemer metal is preferred can be satisfied.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof and a present preferred method of practicing the same proceeds.

In the accompanying drawings I have shown a present preferred embodiment of the invention and have illustrated a present preferred method of practicing the same, in which- Figure l is an elevational view, more or less diagrammatic, of a shotting machine for pouring molten ferrous material into a bath of molten slag in the manufacture of wrought iron by the Aston process, the slag receptacle for receiving the pour also being shown;

Figure 2 is an elevational view to enlarged scale of the shotting machine shown in Figure 1;

Figure 3 is a plan view of the shotting machine; and

Figure 4 is a diagrammatic plan of a portion of a plant for the manufacture of wrought iron showing a shotting machine, an open hearth furnace for preparing molten ferrous material and an overhead crane for transferring the molten ferrous material from the open hearth furnace to the shotting machine.

, Referring now more particularly to the drawings, there is shown in'Figure 4 a portion of a plant layout which may be employed for the manufacture of wrought iron by my improved process and with the use of my improved apparatus, it being understood that the plant layout may be altered as desired, There is shown a shotting machine designated generally by reference numeral 2, a slag receptacle 3 thereunder; an open hearth furnace 4 for melting ferrous material for use in the process and an overhead crane 8 for transferring molten ferrous material tapped from the open hearth furnace to the shotting machine. So far as the apparatus is concerned, each of the elements per se may be of well known form except the shotting machine, which is provided with a tilting ladle 6 adapted to pour through a nozzle. Except for the ladle the shotting machine is substantially like that disclosed in Willie Patent No. 1,933,577. The ladle in addition to being tiltably mounted is also mounted for horizontal reciprocation and for angular oscillation to distribute the pour. The provision for such reciprocation and oscillation is substantially the same as in said Willie patent.

The shotting machine may be mounted alone or it may be one of a group of shotting machines mounted together as disclosed in said Willie patent. As the number of shotting machines employed and the mounting thereof form no part of the present invention, only a single shotting machine has been shown and the specific means for mounting the same has been omitted. The shotting machine is mounted upon a stationary platform at an elevation above that of a track I on which is a car 8 carrying a slag receptacle 9. In Figure 4 the track I is shown as broken off at each end, it being understood that such track may take such form as may be desirable. One form of track is shown in the Willie patent above mentioned. The slag receptacle 9 is provided with trunnions ill by which it may be picked up by an overhead crane for decanting off the excess slag and dumping out the ball.

The shotting machine 2 comprises a reciprocable platform II, a table l2 adapted for oscillatory rotary movement on the platform and the ladle 6 referred to above tiltably mounted on the ferrous material it is disposed substantially in the position shown in Figures 2, 3 and 4 with both the nozzle and the charging opening facing upwardly. Molten ferrous material is poured into the charging opening it of the ladle by the ladle l5 of the overhead crane 5. The ladle 6 may be filled to any convenient height, such, for example, as that indicated by the dot and dash line It in Figure 2, which line is below the pouring orifice and the charging opening.

The platform I i has an opening I! therein and is provided with wheels l8 which rest on rails i9 to permit reciprocation of the platform. The rails iii are carried by the beam 20 of a platform scale having a suitable indicating dial (not shown). Suitable stops 2i limit the reciprocating movement of the platform ii. The shotting machine overlies an opening in the floor upon which it is mounted at an elevation above the track I and the rotary table I2 has a circular opening 22 therein of the same size as the opening H in the platform II so that it is possible upon sufficient tilting of the ladle 6 to pour metal therefrom through the opening 22 in the table, the opening I! in the platform II and the opening in the floor into the slag receptacle 9 disposed beneath the shotting machine. The respective openings l1 and 22 are both open at the lefthand end of the shotting machine shown in each of the figures of the drawings so that no obstruction is offered to the stream delivered by the ladle 3 in any operative position of such ladle.

The means for reciprocating the platform I I includes an electric motor 23 and reduction gearing 24 which serves to connect the motor and the axle to which the wheels l8 at the right-hand end of the platform are secured. A limit switch 25 is connected to the reduction gearing 24 by power transmission mechanism 26 and causes the motor 23 to be reversed at the limits of movement of the platform ll so as to prevent overtravel thereof and insure continuous reciprocation.

The platform II has a circular track 2! surrounding the opening H in the platform. The table 12 is provided with wheels 28 engaging the track 21 so that the table may be given a rotary movement with respect to the platform I i. Stops 29 prevent over-travel of the table and automatic means for oscillating the table on its track include a motor 39 and reduction gearing 3| connecting the motor to one of the wheels 28. A limit switch 32 is driven from the reduction gearing and reverses the motor 30 periodically so that the table l2 executes an oscillatory movement. The ladle 6 has trunnions 33 in bearings 34 on the platform l2 which carries means for tilting the ladle 6 comprising a motor 35 and reduction gearing 36. A tilting shaft 31 is journaled in a housing 33 and carries a tilting gear 39 which is in mesh with the reduction gearing 36. A clutch 40 normally connects the tilting shaft 31 and one of the ladle trunnions 33.

The shotting machine controls are manipulated by an operator whose post is at the left of the shotting machine viewing Figures 2 and 3 and slightly above the level of the ladle 6. Consequently the operator can at all times see the stream of molten ferrous material issuing from the nozzle l3 of the ladle 6 and with a little experience can control the tilting of the ladle so that a substantially constant head of molten ferrous material is maintained in the ladle above the nozzle. Of course at the end of the pour the head of molten ferrous material in the ladle above the nozzle becomes zero as the last of the contents of the ladle passes out, which results in diminution of the size of the stream for a few seconds representing a small proportion of the entire pouring time. This diminution is not substantially detrimental.

After the ladle 6 has been emptied a workman with an iron rod passes the end of the rod through the nozzle l3 simply to insure against a light film of solidified metal sealing the orifice as sometimes happens. However, this film forms only at the very end of the pour and is easily removed by the end of the rod held in the workmans hands and there is no sculling or accretion of solidified ferrous material about the orifice so as to interfere in any way with the cross section or density of the stream.

An attempt has been made in Figure 1 of the drawings to depict in a general way the dense controlled character of the stream of molten ferrous material passing out through the orifice or nozzle of the ladle 6. The stream maintains almost perfectly its generally circular cross-sew tion and spreads very little before striking the surface of the slag bath, By reason of the concentration and density of the stream it penetrates deeply into the slag bath, which is highly desirable for the manufacture of wrought iron of high quality.

While I have shown and described a present preferred embodiment of the invention and a present preferred method of practicing the same, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

I claim: 4

1. A method of making wrought iron by the Aston process, comprising pouring through a stream defining opening molten ferrous material in a compact controlled stream which completely fills said opening formed during at least the greater portion of the pour under a substantially constant head of the molten ferrous material into a bath of molten slag to form a wrought iron sponge ball.

2. A method of making wrought iron by the Aston process, comprising delivering molten ferrous material through a nozzle under substantially constant pressure during at least the greater portion of the delivery into a bath of molten slag to form a wrought iron sponge ball.

3. A method of making wrought iron by the Aston process, comprising delivering molten ferrous material through a nozzle under substantially constant pressure during at least the greater portion of the delivery into a bath of molten slag to form a wrought iron sponge ball and during the delivery shifting over the surface of the slag bath the point at which the ferrous material enters the bath.

4. A method of making wrought iron by the Aston process, comprising pouring molten ferrous material through the nozzle of a nozzled ladle into a bath of molten slag to form a wrought iron sponge ball and during at least the greater portion of the pour progressively tilting the ladle to maintain substantially constant the head of molten ferrous material in the ladle above the nozzle thereof.

5. Apparatus for making wrought iron by the Aston process, comprising a tilting nozzled ladle,

means for controllably tilting the ladle so as to maintain substantially constant during at least part of the pour the head of liquid in the ladle above the nozzle thereof, and means for bodily moving the ladle in a generally horizontal plane during tilting thereof.

6. Apparatus for making wrought iron by the Aston process, comprising a slag receptacle adapted to contain a quantity of molten slag, a pouring receptacle for pouring molten ferrous material into the slag receptacle, the pouring receptacle having a pouring orifice which completely defines the cross-section of the stream of ferrous material poured therethrough, and means for controllably tilting the pourin receptacle whereby during the pour the head of molten ferrous material therein above the orifice may be controlled as desired.

7. Apparatus for making wrought iron by the Aston process, comprising a slag receptacle adapted to contain a quantity of molten slag, a tilting nozzled ladle for pouring molten ferrous material into the slag receptacle and means for controllably tilting such ladle.

8. Apparatus for making wrought iron. by the Aston process, comprising a slag receptacle and a shotting machine for distributing molten ferrous material into a bath of molten slag in the slag receptacle, the shotting machine comprising a tilting nozzled ladle for pouring the ferrous material and means for moving such ladle generally horizontally during pouring.

9. Apparatus for making wrought iron by the Aston process, comprising a slag receptacle adapted to contain a quantity of molten slag, a tilting nozzled ladle for pouring molten ferrous material into the slag receptacle and an open hearth furnace for melting the ferrous material.

10. Apparatus for making wrought iron by the Aston process, comprising a slag receptacle adapted to contain a. quantity of molten slag, means for melting ferrous material whose practical upper regular operating temperature limit is not substantially greater than 3000 F., 8.

pouring receptacle for pouring the molten ferrous material into the slag receptacle, the pouring receptacle having a pouring orifice which .completely defines the cross-section of the stream of ferrous material poured therethrough, and means for controllably tilting the pouring receptacle whereby during the pour the head of molten ferrous material therein above the orifice may be controlled as desired.

11. A method of making wrought iron by the Aston process, comprising melting ferrous material and bringing the same to a temperature not substantially greater than about 3000 F. and pouring such molten ferrous material into a bath of molten slag through a nozzle under substantially constant pressure during at least the greater portion of the pour.

12. A method of making wrought iron by the Aston process, comprising melting ferrous material in an open hearth furnace and pouring the molten ferrous material into a bath of molten slag through the nozzle of a tilting nozzled ladle.

FREDERICK W. WHITE. 

